Variable surface airfoil



May 6, 1941.

J. GERIN 2,241,196

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Patented May 6, 1941 UNITED STATES PATENT OFFICE 2,241,196 VARIABLE, summon Araron.

Jacques Grin, Boulogne-sur-Seine, France Application August 16, 1939, Serial No. 290,348

In France August 2 80laims.

high unitary load,whilst rendering it possibleto fly 01!, land or alight at relatively slow speeds.

The invention particularly concerns a variable surface device applicable to the wings and to all other lifting planes of a flying machine, characterized mainly by the combination of a fixed framework which can be reduced to a simple beam with a rigid covering which constitutes the wing for flight at high speed and which, mounted so-as to be capable of moving along the framework, is connected at its root to a flexible surface mounted on drums so as to be retracted into a fuselage for instance or extended out with the rigid surface for increasing the lifting surface of the wing.

In a form of construction of the device thus defined in its principle, the flexible surface has a depth greater than that of the covering secured to its root, so that the increase of the surface takes place, by increasing both the wingspread and the depth.

The device forming the subject matter of the invention can be applied to all the lifting surfaces of a flying machine; it is suitable as well for the wings proper as for the planes and empennage rudder and aileron surfaces.

Flexible surfaces have already been proposed and constructed, which, mounted .on drums, can spread out along fixed lifting planes for increasing the depth thereof. Said surfaces are composed of a flexible covering, made of rubberized fabric for instance reinforced by ribs arranged in the direction of advance of the airplane, that is to say transversely to the wing-spread.

These ribs are constituted by elements pivoted together so as to give to the extended surfaces any desired curve, eventually automatically variable, whilst straightening so as to be wound on the operating drums. The invention takes advantage,- to a certain extent, of the means utilised in these technics, but it differs therefrom by the fact that the flexible surface constitutes above all only a covering, obviously a lifting covering, of the flxed framework uncovered by the displacement of the rigid covering, the .increase in depth of the lifting surface not being an essential object but a possibility or an even- V tual effect of the invention.

wings of a monoplane airplane the framework of which is constituted by a single beam.

In this application, the invention is characterised by the main following points, which constitute as many features of the same:

1. The rigid covering which forms thelifting surface for flying at high speed is constituted by a profiled caisson or box the root of which is so arranged as to obturate the opening formed in the wall of the fuselage through which the flexible surface passes, said root fltting at the same time in the fuselage so as to withstand the torsional stresses exerted on the wing.

2. The rigid covering according to 1, presses upon the fixed beam through the medium of rollers carried thereby and'by the beam.

3. The rollers of the rigid covering are carried by two carriages arranged at two points of its length and provided with means for locking the same on the flxed beam when said covering is in position for flying with a large surface.

. hooks on the lower face of the flxed beam and two extrados elements pivoted on the first element and the ends of which are guided in the lateral slideways of the flap according to 4.

6. A leading edge of the flexible surface is reinforced by ribs pivoted to the front end of the intrados elements according to 5 and which can be lifted by resilient restoring devices when the flexible surface isspread out.

7. The caisson or rigid covering is controlled in its displacement, at the same time as the ribs of the flexible surface, by an endless chain the links of which come in engagement with the intrados elements of the ribs of said flexible surface. a

8. The flexible su face is connected, to the drum which receives it when it leaves theendless chain, by a spring or its equivalent so as to compensate the variations of speed due to the variations of the diameter of the surface wound on the drum.

9. One and the same engine ensures the positive control of the endless chain and of the drum of the flexible surface.

10. The warping ailerons provided on the caisson or rigid covering are controlled by funicular connections of constant length and movable transmissions which spread out without slack with the rigid covering along the fixed beam.

The accompanying diagrammatic drawings iilustrate, by way of. example only, embodiments for carrying the invention into practice.

Figs. 1, 2and 3 show respectively, in elevation, in front view and in plan view, a monoplane airplane provided with the variable surface device according to the invention.

Fig. 4 is a partial plan view of this same airplane on an enlarged scale.

Fig. 5 is an under plan view of the extrados flap or plate which forms a bridge between the root of the wing and the rigid caisson.

Fig. 6 is a corresponding elevation.

Fig. 7 shows, on an enlarged scale, a cross section made according to I-I of Fig. 6.

Fig. 8 is a partial elevation with longitudinal section, of the fixed beam and of the rigid caisson.

Figs. 9 and 10 are partial cross sections made respectively according to lines II-II and III-III of Fig. 8.

Fig. 11 is a diagrammatic elevation of a rib of the flexible surface.

Fig. 12 is a perspective diagram of the control for the flexible surfaces.

Fig. 13 is a detail of the chain.

Fig. 14 shows another diagram of the device for winding the flexible surface.

Fig. 15 is a diagram of the control for the ailerons.

Fig. 16 is a perspective diagram of a. modification of the control for the ailerons.

In the form of construction contemplated, each wing comprises an inner framework constituted by a beam I (Fig. 4) advantageously in the form of a caisson of constant width, but of uniformly decreasing height from the fuselage 2 up to the end. Said beam can be made in one piece from one wing to the other according to a well known construction of airplanes in general, and of monoplane airplanes in particular. The construction itself moreover only concerns the invention as far as the particular points indicated in the following are concerned.

A rigid covering 3 or caisson constitutes the wing for flying at high speed. It takes a bearing on the beam l as more clearly shown in Figs. 8 to 10, by means of rollers. At its free end, the beam I carries. through the medium of riveted fork members 4, rollers 5 on which bears a roller track 9 riveted on the intrados covering I. The beam I also carries, by means of a fork member 9 lateral rollers 9 and 9* which support and guide the covering or caisson 3 by means of roller tracks l9 and i9.

The covering itself carries, at certain points of its length and at its end, rollers i I through which it transversely presses on the tracks l2 of the beam (Fig. 10) At its root, the covering 3 carries, on the onehand, rollers l4 which bear on the lower face of the beam I, and on the other hand, fork members I! with rollers l9 which'bear on the upper face of the lower edge or track l2 of the beam i.

The caisson} is thus perfectly held in position on the beam whatever may be its longitudinal position on the latter.

In extreme spread out position, the fixation is completed by engaging the fingers l1 and ii of have just been described, corresponds to general technics. Said caisson comprises warping ailerons 2| the particular control system of which will be described later on.

At its root, the caisson 3 is flared at 3 so as to join with the flexible surface and to obturate, according to lines which are suitably studied as far as aerodynamics are concerned, the opening formed in the fuselage for the passage of said flexible surface.

The latter is reinforced by ribs, uniformly distributed on its length, and an arrangement of which is shown by way of example in Fig. 11. Each rib comprises:

An intrados element 22 which presses against and hooks at 23 on the lower face of the beam I by sliding onthe latter when the surface is spread I out.

Means such as rollers or hooks suitable for ensuring the guiding and facilitating the displacement of the element can be provided on the central part 23 of element 22. The latter is extended by a. trailing part 22 the curve of which can be double and automatically variable or not.

On the element 22 are pivoted extrados elements 24 and 25, the pivotal points being shown at 26 and 26 The free ends of said elements engage in lateral slideways 21 of a flap or plate 29 shown in Figs. 5 to 7 and which will be described later on.

When the ribs, during the movement of the flexible surface returning on its drum, leave the beam, within the fuselage, the free ends of the elements 24 and 25 abandon the slideways 21 and fold down, with the portions of the flexible covering they reinforce, on to the lower elements so as to allow said flexible surface to be wound on the drum. On each system of ribs thus described can be advantageously provided a movable nose adapted to constitute a slot in front of the leading edge of the surface when it is spread out. The movable noses 29 of said covering are pivoted at 26 and connected by an elongated eye 30 formed at the end of a bar 3i pivoted at 32 on the element 24 and restored by a sandow 99 having a point of attachment on the part 23. When a constraint other than the thrust of the relative wind acts on the movable covering, the sandow acts to bring and hold the nose 29 in the position shown in the drawings, the bar 81 abutting through its end 92' against the lower face of the rib element 22. When the flexible surface is restored on its drum, the elements 29, 24 and the bar II are folded down on the element 22.

When the rigid caisson 2 and the variable surfaceare spread out by the means which will be described later on, the flap 29 (Figs. 5 and 6) pivoted at 29 at its root is gradually lifted, assisted by the reaction of springs 29', by the displacement of studs eventually provided with rollers and and arranged within the caisson I under the ...surface to which it is connected by its root is ensured, in the embodiment contemplated, by a single electric motor. In the diagram of Fig. 12,

said motor is shown at 39, connected by a gearing down device 3'! to a shaft 38 on which are rigidly secured:

A pulley 39 or a pinion ensuring the connection with the drum 35.

A pinion 40 carried by the beam I, at the root of the latter, and which controls an endless chain 4| .passing on a second pinion 42 carried by the outer end of the beam I.

1 The chain 4| has some of its links 43 shaped as shown in Fig. 13 so as to engage with the elements 22 of the ribs of the flexible surface for guiding it up to the transmission drum 44 loosely mounted on its axis and arranged parallel to the drum 35, in front of the latter. Said links act for displacing in the outlet or inlet direction, the caisson 3 and successively all the ribs of the flexible surface they reinforce.

The chain 4| and its pinion 40 are shown in another position but for carrying out the same principle as previously, in the diagram of Fig. 14. The end of the flexible surface is attached at 45 on the drum 39. The latter is connected to its driving axis through the medium of any suitable resiliently distortable means diagrammatically shown in the form of a spiral spring 46.

This spring is tensioned and expands at the outlet and inlet of the sail or flexible surface for compensating the variations of the diameter of the wound part and thus allows a control of the in the drawings.

pivoted in bearings 59 and 60 of the caisson 3. The lever 51 is connected to the cable 6| which passes on the pulley 62 connected by a link 63 to one end of the rudder-bar 56, comes back on the pulley 64 carried by the beam and is attached at 36 to the root of the caisson.

The lever 58 is connected to the cable 66 which passes over the pulley 62" connected by the link 63 to the other end of the rudder-bar-SG, passes over the pulley 34" secured to the beam and is attached to the fixed point 65 of the caisson.

When the caisson spreads out, the length or the tension of each cable remains constant and by inclining the joy-stick 55 in the direction of The invention, as above stated. is applicable to all the lifting surfaces of an airplane and not only to the wings as in the solution illustrated In particular, empennage planes, of variable surface can be devised according to the same principle as that described in the foregoing. Particularly, the roots of the movable caissons of the horizontal rudders and allerons can be constituted by rigid surfaces which press against the axial tail-fin of the empennage and constitute, when they are spaced apart, supplementary tail-fins for flying with a large surface. Generally speaking the variable surface device according to the invention can be applied 1 as well to the vertical planes as to the longi- This arrangement is indicated herein only by way of example, any other arrangement capable of producing the same effects can be substituted The control of the warping ailerons 2| must be capable of being ensured as well with a reduced surface as with-alarge surface. Two examples of controls satisfying these conditions are illustrated in Figs. 15 and 16.

In the example of Fig. 15, one end of a lever 4'! controlling the aileron 2| is connected to a cable 41' which passes over transmission pulleys 43, 49, 50, SI and 52 to be attached at the fixed point 53 on the root of the caisson 3 of the opposite aileron. The other end-of the lever 41' is connected in the same manner to a cable 4'l which passes over the pulleys 48, 49', 50, 5| and 52' and is attached to the fixed point 53. The lever of the opposite aileron is connected in the same manner to cables which are attached at 53 and 53 on the opposite caisson 3.

The pulleys such as 49-4$ -.5050, Sl-il are secured on the fuselage.

The pulleys such, as 5252 are fixed.

The pulleys such as 4848 are secured on the caissons 3 and move with the latter.

When the caissons 3 move apart, the parts of the cables comprised between the pulleys 48-43 and 50-50 lengthen to the extent according to which the parts comprised between the pulleys 32-52 and the points of attachment 53-53 shorten. The initial tension of the cables remains constant.

By simultaneously displacing the pulleys such as I0 and I0 transversely to the cables, in one direction or the other, the ailerons 2| are set in the suitable direction whatever may be the longitudinal positions of the caissons 3.

In the embodiment shown in Fig. 16, a joy-stick 5! moves a rudder-bar 58 the ends of which are connected to each of the aileron controls. An

aileron 2| is controlled by two levers l1 and 53 tudinal planes of the rudders and ailerons.

What I claim as my invention and desire to secure by Letters Patent is: j

1. A variable surface airfoil device for an airplane or a hydroplane having a fuselage, the combination of a fixed beam mounted transversely on the fuselage with respect to the line of flight, a rigid airfoil encasing said beam and serving. as a wing or airfoil for flying at high speed, means movably mounting said airfoil on said beam so as to. be movable along the same to extreme extended position, and a unitary flexible lifting surface member connected to the root of said rigid covering and stored in a portion of the fuselage when the rigid covering is in retracted position and drawn out and exposed in effective lifting position by moving said rigid covering out along said beam, means in the fuselage for retaining the inner end of said flexible lifting surface member when the same is in extended position and also for receiving the same in retracted position of the rigid covering and flexible surface member.

2. A device according to claim 1, wherein the rigid covering which forms the lifting surface for flying at high speed includes a profiled caisson or box having a root which is arranged in a position to close an opening formed in the wall of the fuselage through which the flexible surface member passes, said root fitting at the same time in the fuselage so as to withstand the torsional stresses exerted on the wing.

3. A device according to claim 1, wherein the beam carries rollers for supporting said covering on the beam and facilitating movement of the rigid covering along said beam and allowing the same to press on the latter.

4. A device according to claim 1, including two carriages spaced along the rigid covering to support the same and 'havingrollers facilitating movement along the beam, and means upon said carriages for locking said rigid covering in its extreme extended position on said beam.

5. A device according to claim 1, including a flap arranged on the upper portion of the beam and pivoted to the root of the latter in a position causing the flap to be lifted and form a bridge up to the extrados of the root of the rigid covering when the latter is drawn out to extended position.

6. A device according to claim 1, including ribs on the flexible surface member comprising an extrados element pressing against and hooking onto the lower portion of the beam, and two extrados elements pivoted upon the first extrados element, and a flap arranged on the upper portion of the beam having lateral slideways for guiding the ends of said two extrados elements.

7. A device according to claim 1, including ribs on the flexible surface member comprising an extrados element pressing against and hooking onto the lower portion of the beam, and two extrados elements pivoted upon the first extrados element, a flap arranged. on the upper portion of the beam having lateral slideways for 

